Engineer&#39;s brake valve



T. H. THOMAS.

ENGINEERS BRAKE VALVE. APPLlcATloN man MN. i9, |921.

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.fl/IIIA infini IMQ/Emo@ Vl-ww@ H THOMAS 'ATTORNEY Patented @et l?,i922.

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THOMAS THOMAS, OF EDGEWOOD, PENNSYLVANIA, ASSIGNOR`TO THE WESTING- HOUSEAIR BRAKE COMPANY, 0F WILMERDING, PENNSYLVANIA, ACORPOBATIGN OFPENNSYLVANIA.

ENGINEERS BRAKE VALVE.

Application filed January 19, 1921. Serial No. 438,468."

brakes, and more particularly to the control y of the main reservoirpressure.

With the present standard liuid pressure brake equipment there isusually provided what is termed a duplex pressure control device havinga maximum pressure head and an excess pressure head for gover-ning theoperation of the steam pump which com-,

presses fluid into the main reservoir.

They maximum pressure head is adjusted for a high main reservoirpressure such as 130 pounds, for example, and the excess pressure headfor a lower main reservoir pressure, such as 90 pounds.

As heretofore operated, the excess pressure head governs the mainreservoir pressure in the full release position of the engineers brakevalve, so that the main reservoir pressure is limited to the lowermaximum pressure of 90 pounds.

This has been found undesirable in some cases, for example, when trainsare being moved down long steep grades, the frequent applications andreleases of the brakes consume so much air that eventually the mainreservoir pressure may not be high enough to permit the recharge of thebrake pipe to the desired standard pressure.

The principal object of my invention is to provide for cutting out theexcess pressure head in the full release position of 4the brake valve,so that in this position, the main reservoir pressure is governed by themaximum pressure head and is therefore maintained at a higher maximumpressure.

In the accompanying drawing, the single figure is a diagrammatic view,partlyin section, of a portion of a locomotive brake equipment,illustrating the application of my improvement.

In the drawing, the duplex pressure controlling device or steam pumpgovernor may comprise a maximum pressure head 1, an excess pressure head2, and a steam controlling valve device 3.

The steam controlling valve device Smay comprise a casing. containing avalve l for controlling the supply of steam to the steam pump whichcompresses air into the usual main reservoir 5. .v f The valve 4 .isoperated by a piston 6, subject on one side vtothe pressureof a spring 7and having the opposite side open toapassage 8. f

The maximum pressure head l-may comprise a casing containing. adiaphragm. 9,

subject on one side to the pressure of an .adjustable spring 10 fand onthe opposite yside/to fluid at main reservoir pressure suplportedthrough pipe l11.

y9 controls a 1 valve y12 for supplying fluid The diaphragm underpressure to passage lSand piston 6.

r The excess pressure head. 2.may kcomprise a casing containing adiaphragm 13, subject on one side to the pressure of an adjustablespring 14 and on the opposite side to fluid under pressure suppliedthrough pipe 15. The diaphragm 13 controls a valve 16 for also supplyingHuid under pressure to pas-l sage 8 and piston 6.

The engineers brake valve 17 may be of the usual construction comprisinga casing having a valve chamber 18, containing arotary slide valve 19,adapted to be operated by a handle 20.

A pipe and passage 21 leads from the usual feed valve device 22 to theseat of the rotary valve 19, and a main reservoir pipe 23 supplies fluidunder pressure from the main reservoir 5 to the rotary valve chamber 18,the usual brake pipe 24 being connected to a passage 25, also leading tothe seat of the rotary valve 19.

A pipe 26 connects the feed valve pipe 21 with the spring chamber 27 ofthe excess pressure head 2 and in full release position of the brakevalve, as shown in the drawing and according to my invention, the pipe2,1 is connected by a port 28 through the rotary valve 19 with therotary valve chamber 18. In full release position, the pipe 15 is alsoconnected to the rotary valve chamber 18 through a port 29. v

It will now be clear, that in the full release position of the engineersbrake valve, as shown in the drawing, since fluid at main reservoirpressure is supplied from the rotary valve chamber 18 through pipe 26 tothe chamber 27, the Huid pressures on opposite sides of the diaphragm 13Will be equal, so that the spring 14 Will operate on the diaphragm 13 tohold the valve 16 closed. f

The excess pressure head 2 Will therefore vbe cut out of action vand themain reservoir standardunder such conditions as hereinbefore stated.

Having now described my invention, what I claim as new and desire tovsecure by Letters Patent, is v 1. The combination With a main reservoirand fa brake valve device having the usualy full'release osition of a dulex ressure n a e vgovernor having a pressure head for limiting themaxlmum pressure 1n the main reservoir to a predetermined high degreeand fa pressure head for limiting the maximum pressurein the mainreservoir to a predetermined lower degree; and means operative'in' fullrelease position of the brake valve device for cutting the low pressurehead out of action.

2. The combination with a brakel valve and a main reservoir, of a duplexpressure governor having a 10W pressure head for limiting the mainreservoir pressure to a predetermined maximum degree and a high pressurehead for limiting the main reservoir pressure rto a higher predeterminedmaximum degree and means for preventing the operation of the 10Wpressure head in the full release position of the brake valve.

3. The combination with a brake valve anda main reservoir, of a duplexpressure governor having a loW pressure head including a diaphragmsubject tothe opposing pressures of an adjustable spring and mainreservoir pressure for limiting the main reservoir pressure to apredetermined maximum and a high pressure head for lime iting the mainreservoir pressure to ahigher maximum degree and means for supplyingfluid at main reservoir pressure to the spring side of said diaphragm inthe full release position of the brake valve.'-

In testimony whereof I have hereunto set my hand.

THOMAS H. THOMAS.

